This invention relates to drilling holes in composite materials such as carboresin laminates and particularly laminates having a resin reinforced with carbon fibers of graphic structure and laminates called carboresins formed by graphite fibers embedded in a matrix of epoxy resin. Materials of the beforementioned type are widely used in the aircraft industry to drill clean holes without de-lamination. Such a drill is used to form a multitude of relatively small diameter holes in building aircraft and heretofore drills used for forming holes in laminate used in that industry have short effective working life. Thus there is not only a need for a drill capable of rapidly forming clean small diameter holes in carboresins and the like materials, but also a need for such a drill which has a long effective working life.